/*
 * Copyright (c) 1999, 2013, Oracle and/or its affiliates. All rights reserved.
 * ORACLE PROPRIETARY/CONFIDENTIAL. Use is subject to license terms.
 *
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 */

package javax.sound.sampled;


/**
 * A mixer is an audio device with one or more lines.  It need not be
 * designed for mixing audio signals.  A mixer that actually mixes audio
 * has multiple input (source) lines and at least one output (target) line.
 * The former are often instances of classes that implement
 * <code>{@link SourceDataLine}</code>,
 * and the latter, <code>{@link TargetDataLine}</code>.  <code>{@link Port}</code>
 * objects, too, are either source lines or target lines.
 * A mixer can accept prerecorded, loopable sound as input, by having
 * some of its source lines be instances of objects that implement the
 * <code>{@link Clip}</code> interface.
 * <p>
 * Through methods of the <code>Line</code> interface, which <code>Mixer</code> extends,
 * a mixer might provide a set of controls that are global to the mixer.  For example,
 * the mixer can have a master gain control.  These global controls are distinct
 * from the controls belonging to each of the mixer's individual lines.
 * <p>
 * Some mixers, especially
 * those with internal digital mixing capabilities, may provide
 * additional capabilities by implementing the <code>DataLine</code> interface.
 * <p>
 * A mixer can support synchronization of its lines.  When one line in
 * a synchronized group is started or stopped, the other lines in the group
 * automatically start or stop simultaneously with the explicitly affected one.
 *
 * @author Kara Kytle
 * @since 1.3
 */
public interface Mixer extends Line {

  /**
   * Obtains information about this mixer, including the product's name,
   * version, vendor, etc.
   *
   * @return a mixer info object that describes this mixer
   * @see Mixer.Info
   */
  public Info getMixerInfo();


  /**
   * Obtains information about the set of source lines supported
   * by this mixer.
   * Some source lines may only be available when this mixer is open.
   *
   * @return array of <code>Line.Info</code> objects representing source lines for this mixer.  If
   * no source lines are supported, an array of length 0 is returned.
   */
  public Line.Info[] getSourceLineInfo();

  /**
   * Obtains information about the set of target lines supported
   * by this mixer.
   * Some target lines may only be available when this mixer is open.
   *
   * @return array of <code>Line.Info</code> objects representing target lines for this mixer.  If
   * no target lines are supported, an array of length 0 is returned.
   */
  public Line.Info[] getTargetLineInfo();


  /**
   * Obtains information about source lines of a particular type supported
   * by the mixer.
   * Some source lines may only be available when this mixer is open.
   *
   * @param info a <code>Line.Info</code> object describing lines about which information is
   * queried
   * @return an array of <code>Line.Info</code> objects describing source lines matching the type
   * requested.  If no matching source lines are supported, an array of length 0 is returned.
   */
  public Line.Info[] getSourceLineInfo(Line.Info info);


  /**
   * Obtains information about target lines of a particular type supported
   * by the mixer.
   * Some target lines may only be available when this mixer is open.
   *
   * @param info a <code>Line.Info</code> object describing lines about which information is
   * queried
   * @return an array of <code>Line.Info</code> objects describing target lines matching the type
   * requested.  If no matching target lines are supported, an array of length 0 is returned.
   */
  public Line.Info[] getTargetLineInfo(Line.Info info);


  /**
   * Indicates whether the mixer supports a line (or lines) that match
   * the specified <code>Line.Info</code> object.
   * Some lines may only be supported when this mixer is open.
   *
   * @param info describes the line for which support is queried
   * @return <code>true</code> if at least one matching line is supported, <code>false</code>
   * otherwise
   */
  public boolean isLineSupported(Line.Info info);

  /**
   * Obtains a line that is available for use and that matches the description
   * in the specified <code>Line.Info</code> object.
   *
   * <p>If a <code>DataLine</code> is requested, and <code>info</code>
   * is an instance of <code>DataLine.Info</code> specifying at
   * least one fully qualified audio format, the last one
   * will be used as the default format of the returned
   * <code>DataLine</code>.
   *
   * @param info describes the desired line
   * @return a line that is available for use and that matches the description in the specified
   * {@code Line.Info} object
   * @throws LineUnavailableException if a matching line is not available due to resource
   * restrictions
   * @throws IllegalArgumentException if this mixer does not support any lines matching the
   * description
   * @throws SecurityException if a matching line is not available due to security restrictions
   */
  public Line getLine(Line.Info info) throws LineUnavailableException;

  //$$fb 2002-04-12: fix for 4667258: behavior of Mixer.getMaxLines(Line.Info) method doesn't match the spec

  /**
   * Obtains the approximate maximum number of lines of the requested type that can be open
   * simultaneously on the mixer.
   *
   * Certain types of mixers do not have a hard bound and may allow opening more lines.
   * Since certain lines are a shared resource, a mixer may not be able to open the maximum
   * number of lines if another process has opened lines of this mixer.
   *
   * The requested type is any line that matches the description in
   * the provided <code>Line.Info</code> object.  For example, if the info
   * object represents a speaker
   * port, and the mixer supports exactly one speaker port, this method
   * should return 1.  If the info object represents a source data line
   * and the mixer supports the use of 32 source data lines simultaneously,
   * the return value should be 32.
   * If there is no limit, this function returns <code>AudioSystem.NOT_SPECIFIED</code>.
   *
   * @param info a <code>Line.Info</code> that describes the line for which the number of supported
   * instances is queried
   * @return the maximum number of matching lines supported, or <code>AudioSystem.NOT_SPECIFIED</code>
   */
  public int getMaxLines(Line.Info info);


  /**
   * Obtains the set of all source lines currently open to this mixer.
   *
   * @return the source lines currently open to the mixer. If no source lines are currently open to
   * this mixer,  an array of length 0 is returned.
   * @throws SecurityException if the matching lines are not available due to security restrictions
   */
  public Line[] getSourceLines();

  /**
   * Obtains the set of all target lines currently open from this mixer.
   *
   * @return target lines currently open from the mixer. If no target lines are currently open from
   * this mixer, an array of length 0 is returned.
   * @throws SecurityException if the matching lines are not available due to security restrictions
   */
  public Line[] getTargetLines();

  /**
   * Synchronizes two or more lines.  Any subsequent command that starts or stops
   * audio playback or capture for one of these lines will exert the
   * same effect on the other lines in the group, so that they start or stop playing or
   * capturing data simultaneously.
   *
   * @param lines the lines that should be synchronized
   * @param maintainSync <code>true</code> if the synchronization must be precisely maintained
   * (i.e., the synchronization must be sample-accurate) at all times during operation of the lines
   * , or <code>false</code> if precise synchronization is required only during start and stop
   * operations
   * @throws IllegalArgumentException if the lines cannot be synchronized. This may occur if the
   * lines are of different types or have different formats for which this mixer does not support
   * synchronization, or if all lines specified do not belong to this mixer.
   */
  public void synchronize(Line[] lines, boolean maintainSync);

  /**
   * Releases synchronization for the specified lines.  The array must
   * be identical to one for which synchronization has already been
   * established; otherwise an exception may be thrown.  However, <code>null</code>
   * may be specified, in which case all currently synchronized lines that belong
   * to this mixer are unsynchronized.
   *
   * @param lines the synchronized lines for which synchronization should be released, or
   * <code>null</code> for all this mixer's synchronized lines
   * @throws IllegalArgumentException if the lines cannot be unsynchronized. This may occur if the
   * argument specified does not exactly match a set of lines for which synchronization has already
   * been established.
   */
  public void unsynchronize(Line[] lines);


  /**
   * Reports whether this mixer supports synchronization of the specified set of lines.
   *
   * @param lines the set of lines for which synchronization support is queried
   * @param maintainSync <code>true</code> if the synchronization must be precisely maintained
   * (i.e., the synchronization must be sample-accurate) at all times during operation of the lines
   * , or <code>false</code> if precise synchronization is required only during start and stop
   * operations
   * @return <code>true</code> if the lines can be synchronized, <code>false</code> otherwise
   */
  public boolean isSynchronizationSupported(Line[] lines, boolean maintainSync);


  /**
   * The <code>Mixer.Info</code> class represents information about an audio mixer,
   * including the product's name, version, and vendor, along with a textual
   * description.  This information may be retrieved through the
   * {@link Mixer#getMixerInfo() getMixerInfo}
   * method of the <code>Mixer</code> interface.
   *
   * @author Kara Kytle
   * @since 1.3
   */
  public static class Info {

    /**
     * Mixer name.
     */
    private final String name;

    /**
     * Mixer vendor.
     */
    private final String vendor;

    /**
     * Mixer description.
     */
    private final String description;

    /**
     * Mixer version.
     */
    private final String version;

    /**
     * Constructs a mixer's info object, passing it the given
     * textual information.
     *
     * @param name the name of the mixer
     * @param vendor the company who manufactures or creates the hardware or software mixer
     * @param description descriptive text about the mixer
     * @param version version information for the mixer
     */
    protected Info(String name, String vendor, String description, String version) {

      this.name = name;
      this.vendor = vendor;
      this.description = description;
      this.version = version;
    }


    /**
     * Indicates whether two info objects are equal, returning <code>true</code> if
     * they are identical.
     *
     * @param obj the reference object with which to compare this info object
     * @return <code>true</code> if this info object is the same as the <code>obj</code> argument;
     * <code>false</code> otherwise
     */
    public final boolean equals(Object obj) {
      return super.equals(obj);
    }

    /**
     * Finalizes the hashcode method.
     *
     * @return the hashcode for this object
     */
    public final int hashCode() {
      return super.hashCode();
    }

    /**
     * Obtains the name of the mixer.
     *
     * @return a string that names the mixer
     */
    public final String getName() {
      return name;
    }

    /**
     * Obtains the vendor of the mixer.
     *
     * @return a string that names the mixer's vendor
     */
    public final String getVendor() {
      return vendor;
    }

    /**
     * Obtains the description of the mixer.
     *
     * @return a textual description of the mixer
     */
    public final String getDescription() {
      return description;
    }

    /**
     * Obtains the version of the mixer.
     *
     * @return textual version information for the mixer
     */
    public final String getVersion() {
      return version;
    }

    /**
     * Provides a string representation of the mixer info.
     *
     * @return a string describing the info object
     */
    public final String toString() {
      return (name + ", version " + version);
    }
  } // class Info
}
